Description of the Related Art
The invention relates to a system for outputting signals of a digital control system to peripheral units and, more particularly, to a system for inputting and/or outputting such signals to peripheral units which are connected via a bus system, output registers and output stages to a control unit.
The invention relates further to a system for inputting and/or outputting signals of a digital control system from and/or to peripheral units, wherein an output side of an input circuit and an input side of an output circuit are connected to a control unit, and wherein the input and/or output circuits are monitored.
The control of machines and installations with the aid of digital control functions frequently also includes functions in which errors can lead to considerable material damage or even risks to persons. Especially in the case of complex structures, therefore, very great demands are placed upon the reliability of individual system components. It is necessary, therefore, when switching-on or during the operation of an installation to realize an error diagnosis in order to detect errors quickly and to bring them under control with regard to safety.
Monitoring is necessary, particularly in the vicinity of the peripheral units and interfaces.
These demands apply particularly to systems for the control of printing presses, because, in such a case, firstly, the number of sensors and actuators is very high and their operation has to be adapted to the specific requirements. Secondly, personnel trained in the field of electronics is often not available for the operation of printing presses
It is accordingly an object of the invention of the instant application to provide a system for inputting and/or outputting signals of a digital control system which permits such monitoring in a reliable manner yet maintains the associated expense as low as possible. In this connection, it is a further object of the invention to provide the system according to the invention with a high degree of flexibility.